Advanced Materials and Joining Course 2024/2025 PDF

ADVANCED MATERIALS AND JOINING Adhesive Bonding Course 2024/2025  Introduction Theory of adhesion Surface treatment Adhesive selection Control (destructive and non-destructive tests) 2  INTRODUCTION Advanced mate...

ADVANCED MATERIALS AND JOINING Adhesive Bonding Course 2024/2025  Introduction Theory of adhesion Surface treatment Adhesive selection Control (destructive and non-destructive tests) 2  INTRODUCTION Advanced materials  Composite Materials Joining technologies Mechanical joints Welding ADHESIVES 3  INTRODUCTION: APPLICATIONS Aeronautical industry 4  INTRODUCTION: APPLICATIONS Automotive industry Lotus Elise 5  INTRODUCTION: APPLICATIONS Rail industry Hexcel composites 6  INTRODUCTION: APPLICATIONS Marine industry Sika 7  INTRODUCTION: APPLICATIONS Bridge over River Fulda (Kassel, Germany) Civil industry Ultra high performance concrete (UHPC)-steel Deck plates are glued to the upper chords of the truss structure The Helix Bridge (London, UK) Glass and steel retractable footbridge The glass is bonded to the transoms with structural- grade adhesive Fehling, 2013 8  INTRODUCTION: APPLICATIONS Electrical industry Shoe industry 9 INTRODUCTION: ADVANTAGES AND LIMITATIONS ADVANTAGES Uniform stress distribution Ability to joint dissimilar materials and thin-sheet materials Increase in design flexibility (e.g. honeycomb structures) Smooth surfaces Continuous contact between surfaces In general, reduce costs LIMITATIONS Peeling and cleavage Limited resistance to extreme conditions (heat, temperature…) Need of fixing tools during curing: economic disadvantage Surface treatment Adhesives are frequently cured at high temperature Difficult quality control: development of non-destructive testing 10  THEORY OF ADHESION Why do adhesives stick? 11  THEORY OF ADHESION Theories of adhesion Physical Chemical Mechanical adsorption adsorption interlocking - Surface forces - Chemical bond - High surface area -Most important - Requires good - Occurs in all wettability bonds 12  THEORY OF ADHESION Forces involved All the bonds are forces acting in very short distances (some angstroms (1 A = 10-10 m = 0.0001 mm)). Secondary bonds Primary bonds 13  THEORY OF ADHESION Surface roughness ≈ 0.5 μm 14  THEORY OF ADHESION Surface roughness Roughness = 1000 x distance of action of the bonding forces But if liquid… 15  THEORY OF ADHESION Wetting 16  THEORY OF ADHESION Wetting Liquid/Solid Unbalance of attraction forces at the surface of solids/liquids  surface energy/surface tension 17  THEORY OF ADHESION Wetting 18  THEORY OF ADHESION Wetting: spreading Principle of minimum energy Surfaces with high energy Surfaces with low energy Hard materials Soft materials High melting point Low melting point Metals, ceramics Organic solids, polymers 19  THEORY OF ADHESION Wetting: spreading 20  THEORY OF ADHESION Wetting: spreading Same solid Same liquid 21  THEORY OF ADHESION How can joints be improved? SURFACE TREATMENTS 22  SURFACE TREATMENTS Characteristics that affect adhesion Contamination: oils, greases, fingerprints, mold release agents, etc. have low surface energy  Decrease adhesion Weak boundary layer: contaminant films, oxide layers, rust, corrosion, scale, and loose surface particles, etc. 23  SURFACE TREATMENTS In surface treatment, the following operations can occur: 1- Material removal 2- Chemical modification of the surface 3- Change of the surface topography Good treatment Bad treatment 24  SURFACE TREATMENTS Classification Passive processes No chemical alteration Clean the surface Remove substances that are weakly attached Active processes Chemical transformation Metals  formation of a well-defined oxide or structure Polymers  formation of polar groups that increase surface energy and adhesion Last treatment when high strength and durability are required 25  SURFACE TREATMENTS Classification Pasive treatments Active treatments Solvents Acid etching Chemical cleaning Primers Abrasive methods: sanding, Anodizing (metals) shot-blasting Flame treatment, plasma (polymers) 26  SURFACE TREATMENTS Tests Surface energy Roughness 27 28  ADHESIVE SELECTION Classification Function Mechanical Hardening Physical form performance mechanism Structural Liquid Non-structural Rigid Chemical reaction Paste Elastic Loss of solvent or Solid water Hardening from the melt 29  ADHESIVE SELECTION Classification by function Structural Non-structural Epoxies Silicones Polyurethanes Cyanoacrylates Acrylics Hot melts 30  ADHESIVE SELECTION Classification by mechanical performance Rigid/Stiff Elastic Epoxies Silicones Acrylics Polyurethanes Cyanoacrylates Hot melts 31  ADHESIVE SELECTION Classification by hardening mechanism Chemical reaction Loss of solvent of water Hardening from the melt Two parts Contact adhesives Thermoplastics Cure by humidity White glue Hot melts Cure by radiation (light, UV…) Catalized by the substrate 32  ADHESIVE SELECTION Epoxies Polyurethanes Silicones One or two parts Cure by moisture Cure by moisture Strong but brittle Elastic structural adhesive Elastic and high water resistance Aircrafts, sport equipment Automotive industry Molds, household appliances Acrylics Acrylics – Anaerobics Acrylics – Cyanoacrylates One or two parts Cure by absence of oxygen and Cure by substrates moisture Lower strength than epoxies triggered by metallic ions Rigid with bad gap filling Rapid assemble of structures Threadlockers Optical and electronics Pressure-sensitive adhesive Cure by pressure Rapid assembly Medicine, labelling 33  ADHESIVE SELECTION Selection process Substrate Product requirements Adhesive selection Experimental validation Design and loading Service environment 34  CONTROL: DESTRUCTIVE TESTING Loading modes It is important to consider the environment where the adhesive joint is going to be during its in- service life. Polymers are sensitive to chemicals, temperature, moisture and radiation. 35  CONTROL: DESTRUCTIVE TESTING Shear: single lap joints 𝐹𝐹 (𝑁𝑁) 𝜎𝜎(𝑀𝑀𝑀𝑀𝑀𝑀) = 𝐴𝐴( 𝑚𝑚𝑚𝑚2 ) 36  CONTROL: DESTRUCTIVE TESTING Tension: pull-off tests 𝐹𝐹 (𝑁𝑁) 𝜎𝜎(𝑀𝑀𝑀𝑀𝑀𝑀) = 𝐴𝐴( 𝑚𝑚𝑚𝑚2 ) 37  CONTROL: DESTRUCTIVE TESTING Peel and cleavage 𝐹𝐹 (𝑁𝑁) 𝑃𝑃𝑃𝑃𝑃𝑃𝑃𝑃 𝑠𝑠𝑠𝑠𝑠𝑠𝑠𝑠𝑠𝑠𝑠𝑠𝑠𝑠𝑠 (𝑁𝑁/𝑚𝑚𝑚𝑚) = 𝑙𝑙(𝑚𝑚𝑚𝑚) 38  CONTROL: DESTRUCTIVE TESTING Creep and Fatigue - Static loads are applied gradually and remain constant over time. - Cyclic loads involve repetitive or fluctuating forces that can cause stress and fatigue in materials. - Creep refers to the slow, time-dependent deformation of a material under a constant load. All types of loads are critical considerations in the selection and performance of adhesives, as they determine the durability and longevity of the bonded joints under different operating conditions. 39  CONTROL: NON-DESTRUCTIVE TESTING Visual inspection Porosity, misalignments, non-uniform adhesive thickness, etc. Da Silva, 2011 40  CONTROL: NON-DESTRUCTIVE TESTING Tap test Tapping on the bonded joint Sharp clear tone  good adhesion Dull hollow tone  void or unattached area Can be instrumented (solenoid operated hammer and microphone pickup) 41  CONTROL: NON-DESTRUCTIVE TESTING Ultrasonic inspection There are a transmitter and a receiver of ultrasounds, which can be in one or two probes. 42  CONTROL: NON-DESTRUCTIVE TESTING Laser ultrasonic inspection Ultrasounds are generated and detected by laser. 43  CONTROL: NON-DESTRUCTIVE TESTING Acoustic emission Joint must be loaded (semi-destructive) Stress waves emitted by crack propagation or micro-cracking are recorded with piezoelectric transducers The only method that can detect poor adhesion An, 2014 44  CONTROL: NON-DESTRUCTIVE TESTING Radiography Voids or discontinuities Contrast improved with metal powder or other suitable filler 45  CONTROL: NON-DESTRUCTIVE TESTING Thermal methods: Infrared thermography Ruwandi Fernando, 2019 46  Structural? Rigid or flexible? Curing mechanism Advantages Disadvantages - Storage EPOXY 1C Yes Rigid Heat - Strength and durability - Cures at high temperature - Slow curing EPOXY 2C Yes Rigid Chemical reaction - Strength and durability - Mixture (voids) - Brittleness - Good strength at low temp - Limited temperature and UV POLYURETHANE Yes Flexible Moisture - Toughness resistance - Wetting ability - Low impact of surface ACRYLIC Yes Rigid Chemical reaction preparation - Mixture (voids) - Fast curing - Good sealing capability - Cannot be painted SILICONE No Flexible Moisture - Good humidity and UV - Low strength resistance - Cannot bond large areas ACRYLIC: No Rigid Substrate moisture - Fast curing - Brittle CYANOACRYLATE - Bad gap filling Absence of air and ACRYLIC: ANAEROBIC No Rigid presence of metallic - Little surface preparation - Thin bondlines ions - Fast assembly - Limited mechanical DOUBLE-SIDED TAPE No Flexible Pressure - Reversible joint resistance - Fast curing - Limited mechanical and HOTMELT No Flexible Solidification - Reversible joint thermal resistance Chapter 2 Materials Description  Review - Basic knowledge of Materials Science and Engineering is assumed, but not needed (we will review the main points) - We will focus on composite materials, but not only - These lessons will be mostly qualitative Instituto de Investigación Tecnológica Eva Paz Jiménez DIM-ICAI DIM-ICAI J.C.– del Escuela TécnicaJavier Real Munilla – Y. Ballesteros Superior de Ingeniería(2013-2014) ICAI 05 de julio de 2012 2  Scope ▪ Typical materials available for engineers can be broadly divided in four main categories: ▪ Metals ▪ Plastics ▪ Ceramics ▪ Composites Composite materials Laminated Sandwich Instituto de Investigación Tecnológica Eva Paz Jiménez DIM-ICAI DIM-ICAI J.C.– del Escuela TécnicaJavier Real Munilla – Y. Ballesteros Superior de Ingeniería(2013-2014) ICAI 05 de julio de 2012 3  Definition ▪ These materials are made from two or more constituent materials. ▪ These constituents… have significantly different physical and chemical properties usually can be combined at different proportions for different final properties of the composite remain separated within the finished structure by a macroscopic interface ▪ They have better properties than any of their constituents acting alone ▪ One of the constituents is usually called matrix while the others are called reinforcements Instituto de Investigación Tecnológica Eva Paz Jiménez DIM-ICAI DIM-ICAI J.C.– del Escuela TécnicaJavier Real Munilla – Y. Ballesteros Superior de Ingeniería(2013-2014) ICAI 05 de julio de 2012 4  Overview ❑ Natural f.e: Wood, cellulose fibers in lignin matrix ❑ Engineered According to the matrix material: Ceramic Matrix Composite (CMC) Metal Matrix Composite (MMC) Polymer Matrix Composite (PMC) According to the reinforcements shape: Particles (macro-, micro-, nano-) Continuous fibers (short, long) Instituto de Investigación Tecnológica Eva Paz Jiménez DIM-ICAI DIM-ICAI J.C.– del Escuela TécnicaJavier Real Munilla – Y. Ballesteros Superior de Ingeniería(2013-2014) ICAI 05 de julio de 2012 5  Why composite materials? Advantages ❑ They can reach design specifications in terms of stiffness or resistance while reducing weight compared to conventional materials (steel, Al alloys) High specific stiffness and specific strength ❑ They provide increased impact resistance and improved fatigue behavior ❑ Good dumping properties for vibrations ❑ Reduced costs for the whole life cycle can be reached ❑ Good chemical stability can be reached, high corrosion resistance ❑ Design flexibility ❑ Dimensional stability (CTE as desired) ❑ Manufacturing techniques for complex parts and contours are available ❑ They can even include self-monitoring features, as embedded active or passive sensors (smart materials) Instituto de Investigación Tecnológica Eva Paz Jiménez DIM-ICAI DIM-ICAI J.C.– del Escuela TécnicaJavier Real Munilla – Y. Ballesteros Superior de Ingeniería(2013-2014) ICAI 05 de julio de 2012 6  Why composite materials? Disadvantages ❑ The materials cost is very high compared to steel or even aluminum ❑ Manufacturing techniques for high-volume production are not completely standardized and they are very sensitive to the part design ❑ Lack of exhaustive databases for designing compared to metals. Properties can vary significantly depending on suppliers ❑ Experimental tests are usually mandatory, specially for ageing ❑ Limited temperature resistance ❑ Some of them are toxic or not comply criteria for low-smoke or toxicity in case of fire ❑ Dimensional stability (moisture absorption) Instituto de Investigación Tecnológica Eva Paz Jiménez DIM-ICAI DIM-ICAI J.C.– del Escuela TécnicaJavier Real Munilla – Y. Ballesteros Superior de Ingeniería(2013-2014) ICAI 05 de julio de 2012 7  Constituents Matrix: Reinforcements: It holds reinforcements position: They carry the load (70 to 90%) (it binds the fibers together and transfers They provide increased stiffness the load to the fibers) Strength and structural properties It provides protection to chemical Impact and fracture properties attack or mechanical damage (wear) Electrical properties (as desired) Mechanical stability, it reduces crack Shape is defined by manufacturing propagation method Matrix requirements Reinforcement requirements Shear resistance Shape and orientation as designed Tenacity Volume fraction as designed Humidity and environment resistance Matrix compatibility (chemical and Low Cost structural) Instituto de Investigación Tecnológica Eva Paz Jiménez DIM-ICAI DIM-ICAI J.C.– del Escuela TécnicaJavier Real Munilla – Y. Ballesteros Superior de Ingeniería(2013-2014) ICAI 05 de julio de 2012 8  Matrix materials Thermosets General highlights Polymeric Matrix (PMCs) Epoxy Stronger Termoset polymers Phenolics More brittle Polyester Higher service temperature Termoplastic polymers Vinylester Once cured: permanent shape Cyanate esters (Irreversible reaction) Metallic Matrix (MMCs) Thermoplastic Aluminum alloys Titanium alloys Polyethilene More ductile Copper alloys Polypropylene They melt at Tm temperature Acetal Moldable Ceramic Matrix (CMCs) Nylon Recyclable Polyester Silicates Teflon Alumina Graphite Instituto de Investigación Tecnológica Eva Paz Jiménez DIM-ICAI DIM-ICAI J.C.– del Escuela TécnicaJavier Real Munilla – Y. Ballesteros Superior de Ingeniería(2013-2014) ICAI 05 de julio de 2012 9  Reinforcements materials (PMCs) Relative Cost Typical materials Carbon Aramid Glass Properties Instituto de Investigación Tecnológica Eva Paz Jiménez DIM-ICAI DIM-ICAI J.C.– del Escuela TécnicaJavier Real Munilla – Y. Ballesteros Superior de Ingeniería(2013-2014) ICAI 05 de julio de 2012 10  Reinforcements materials (PMCs) Shape Fibers Short Continuous Organic Fabric Long Discontinuous Inorganic Non-fabric Diameter Carbon (5 µm) Aramid (10 – 15 µm) Glass (5-25 µm) Boron (100 µm) Fabrics: Unidirectional, Woven, Multiaxial Multiaxial Woven Instituto de Investigación Tecnológica Eva Paz Jiménez DIM-ICAI DIM-ICAI J.C.– del Escuela TécnicaJavier Real Munilla – Y. Ballesteros Superior de Ingeniería(2013-2014) ICAI 05 de julio de 2012 11  Product fabrication (PMCs) Forming At this stage, “raw” composite material is manufactured Simple geometries can be made as rods, sheets,… Machining But also complex geometries (near to final part shape) can Joining be manufactured using specific techniques Finishing Material properties will depend on (but not only): Constituents Volume fractions Shape, geometry, orientation Processing quality Additives Processing parameters: (Temperature, pressure, radiation,…) Instituto de Investigación Tecnológica Eva Paz Jiménez DIM-ICAI DIM-ICAI J.C.– del Escuela TécnicaJavier Real Munilla – Y. Ballesteros Superior de Ingeniería(2013-2014) ICAI 05 de julio de 2012 12  Forming: examples Disperse Prepegs Plies >> Laminate Sandwich: Laminated Honeycomb Ref: M D Banea and L F M da Silva. Proceedings of the Institution of Mechanical Engineers, Part L: Journal of Materials Design and Applications 2009 223: 1 (2012) Instituto de Investigación Tecnológica Eva Paz Jiménez DIM-ICAI DIM-ICAI J.C.– del Escuela TécnicaJavier Real Munilla – Y. Ballesteros Superior de Ingeniería(2013-2014) ICAI 05 de julio de 2012 13  Product fabrication (PMCs) Forming As opposite to metals, composite parts are not intensively Machining machined Special tools and techniques are required Joining Finishing Main objectives of machining composites: Create holes, slots or some other features that are not possible to obtain during manufacturing Reach desired tolerances Surface preparation Surface finish Prototyping Instituto de Investigación Tecnológica Eva Paz Jiménez DIM-ICAI DIM-ICAI J.C.– del Escuela TécnicaJavier Real Munilla – Y. Ballesteros Superior de Ingeniería(2013-2014) ICAI 05 de julio de 2012 14  Product fabrication (PMCs) Forming The possibility of manufacturing composites in complex Machining shapes reduces the number of joints, but sometimes they Joining cannot be avoided. Finishing Also, assemblies need joints Types of joints: Adhesive bonding Mechanical joints Direct Ancillary parts Physical/chemical joints For PMCs, adhesive bonding is usually preferred for parts and adhesive or bolted joints for assemblies Instituto de Investigación Tecnológica Eva Paz Jiménez DIM-ICAI DIM-ICAI J.C.– del Escuela TécnicaJavier Real Munilla – Y. Ballesteros Superior de Ingeniería(2013-2014) ICAI 05 de julio de 2012 15  Product fabrication (PMCs) Forming Functional coatings Machining Joining ✓ To protect against environmental degradation ✓ To provide wear resistance Finishing ✓ To provide electrical insulation or conductivity Non - functional coatings ✓ Paints ✓ To improve appearance ✓ Metal like look ✓ To improve tactile sensation Instituto de Investigación Tecnológica Eva Paz Jiménez DIM-ICAI DIM-ICAI J.C.– del Escuela TécnicaJavier Real Munilla – Y. Ballesteros Superior de Ingeniería(2013-2014) ICAI 05 de julio de 2012 16  Properties evaluation It is possible to predict mechanical properties of a composite material. Constituents properties and volume fractions are needed. Weighted arithmetic mean based on volume fractions is directly used for density or Young modulus based in some assumptions (Rule of mixtures). This procedure gives a rough number for first design. Real properties should be tested or supplied by manufacturer for further use. m = Volumematrix c = m  m + r  r VolumeComposite Volumereinforcements r = VolumeComposite Ec = m Em + r Er Em Er Ec = m Er + r Em Instituto de Investigación Tecnológica Eva Paz Jiménez DIM-ICAI DIM-ICAI J.C.– del Escuela TécnicaJavier Real Munilla – Y. Ballesteros Superior de Ingeniería(2013-2014) ICAI 05 de julio de 2012 17  Model I (Longitudinal load) Voigt Model Assumptions: Fibers are parallel to the load Matrix and fibers are perfectly bonded Same strain for fiber and matrix Load is supported by all the fibers and the matrix Poisson effects are neglected Fc = Fm + F f  c Ac =  m Am +  f A f ( c =  m =  f ) Ec  c Ac = Em m Am + E f  f A f Am Af Ec = E m + Ef Ac Ac Ec = m E m + f E f Instituto de Investigación Tecnológica Eva Paz Jiménez DIM-ICAI DIM-ICAI J.C.– del Escuela TécnicaJavier Real Munilla – Y. Ballesteros Superior de Ingeniería(2013-2014) ICAI 05 de julio de 2012 18  Model I (Longitudinal load) Instituto de Investigación Tecnológica Eva Paz Jiménez DIM-ICAI DIM-ICAI J.C.– del Escuela TécnicaJavier Real Munilla – Y. Ballesteros Superior de Ingeniería(2013-2014) ICAI 05 de julio de 2012 19  Model II (Transversal load) Reuss Model Transversal load Fibers are normal to load direction Both matrix and fibers are supporting the same stress ( c =  m =  f )  c = m m + f  f  = Ec  c = E m  m = E f  f σ   = m + f Ec Em Ef 1 m f = + Ec E m E f Em E f Ec = m E f + f Em Instituto de Investigación Tecnológica Eva Paz Jiménez DIM-ICAI DIM-ICAI J.C.– del Escuela TécnicaJavier Real Munilla – Y. Ballesteros Superior de Ingeniería(2013-2014) ICAI 05 de julio de 2012 20  Properties evaluation Rule of mixtures is usually true at low strains (stage I) At stage II, matrix deformation and Poisson effects appear Instituto de Investigación Tecnológica Eva Paz Jiménez DIM-ICAI J.C. del Real Escuela Técnica – Y. Ballesteros Superior de Ingeniería(2013-2014) ICAI 05 de julio de 2012 21  Metallic Matrix Composites (MMC) ▪ Designation: ▪ Metal alloy of the matrix (or pure metal): Fe, Steel, Al, Cu, Ti, … ▪ Volume fraction ▪ Material of reinforcements: Metallic, Ceramic ▪ Shape of reinforcements ▪ Examples: ▪ Designation is not really exhaustive… ✓ 6061Al 30 SiCp ✓ Consolidation process? ✓ 6082Al 25 SiCf ✓ Any thermal treatment during or after fabrication? ✓ Fiber orientations? ✓ … Instituto de Investigación Tecnológica Eva Paz Jiménez DIM-ICAI DIM-ICAI J.C.– del Escuela TécnicaJavier Real Munilla – Y. Ballesteros Superior de Ingeniería(2013-2014) ICAI 05 de julio de 2012 22  Metallic Matrix o Pure metals: Crystallographic arrangement of atoms Metallic bonding (“electronic cloud”) ▪ High electrical and thermal conductivity ▪ Moderate strength and hardness ▪ High ductibility and plastic deformation ▪ Moderate to high melting temperature ▪ Posible magnetic properties Instituto de Investigación Tecnológica Eva Paz Jiménez DIM-ICAI DIM-ICAI J.C.– del Escuela TécnicaJavier Real Munilla – Y. Ballesteros Superior de Ingeniería(2013-2014) ICAI 05 de julio de 2012 23  Metallic Matrix o Endless possibilities to change basic properties are available: ✓ Alloys ✓ Intermetallic compounds ✓ Thermal treatments ✓ Work hardening ✓ Manufacturing processes ✓ Ageing ✓ … Instituto de Investigación Tecnológica Eva Paz Jiménez DIM-ICAI DIM-ICAI J.C.– del Escuela TécnicaJavier Real Munilla – Y. Ballesteros Superior de Ingeniería(2013-2014) ICAI 05 de julio de 2012 24  Metallic Matrix o Then, why to develop MMCs?: Usually combined with ceramics… ✓ Wear resistance ✓ Mechanical properties ✓ Radiation resistance ✓ Effects on ageing ✓ Effects at atomic level: diffusion, grain boundaries, … Possible degradation: Embrittlement Initiation of cracks: Cohesion matrix/ceramic Reduces machinability Instituto de Investigación Tecnológica Eva Paz Jiménez DIM-ICAI DIM-ICAI J.C.– del Escuela TécnicaJavier Real Munilla – Y. Ballesteros Superior de Ingeniería(2013-2014) ICAI 05 de julio de 2012 25  Metallic Matrix: Steels ▪ Steel-based composites: to improve wear resistance ▪ Most popular: ✓ High Speed Steel (HSS) + Hard ceramic reinforcement (wear) ❖ Si, V, W, Mo, Cr + C or Al2O3 ▪ Powder Metallurgy preferred (mov) Bending strength and fracture toughness in dependence on the HP size and spacing Comparison of wear resistant MMC and white cast iron, Wear, Vol. 254 (2003) Instituto de Investigación Tecnológica Eva Paz Jiménez DIM-ICAI DIM-ICAI J.C.– del Escuela TécnicaJavier Real Munilla – Y. Ballesteros Superior de Ingeniería(2013-2014) ICAI 05 de julio de 2012 26  Metallic Matrix: Aluminum alloys Al alloys: Low density, Low melting temperature, Corrosion resistance, Machinability, Conductivity o Casting alloys (fibers reinforcements) Casting methods (mov) o Wrought alloys (particulate reinforcements) Powder Metallurgy o Composite parts (mov) Mid-fuselage structure of Space Shuttle Orbiter showing The P100/6061 Al high-gain antenna wave guides/ boron-aluminum tubes. (U.S. Air Force/NASA) boom for the Hubble Space Telescope (HST) 45% weight savings over Al alloy CTE, stiffness and wave guide Instituto de Investigación Tecnológica Eva Paz Jiménez DIM-ICAI DIM-ICAI J.C.– del Escuela TécnicaJavier Real Munilla – Y. Ballesteros Superior de Ingeniería(2013-2014) ICAI 05 de julio de 2012 27  Metallic Matrix: Aluminum alloys Instituto de Investigación Tecnológica Eva Paz Jiménez DIM-ICAI DIM-ICAI J.C.– del Escuela TécnicaJavier Real Munilla – Y. Ballesteros Superior de Ingeniería(2013-2014) ICAI 05 de julio de 2012 28  Metallic Matrix: Copper and copper alloys Cu alloys: High electrical & thermal conductivity, Ductility, Corrosion resistance, Antimicrobical… Cu alloys Composites: ✓ Improve mechanical properties of Cu o or… “Improve the reinforcements”! Long continuous Matrix fiber (NbTi) (OFHC Copper) Fracture surface of a Cu/SiCf Cross-sectional SEM image of Superconducting NbTi coil (CIEMAT) Instituto de Investigación Tecnológica Eva Paz Jiménez DIM-ICAI DIM-ICAI J.C.– del Escuela TécnicaJavier Real Munilla – Y. Ballesteros Superior de Ingeniería(2013-2014) ICAI 05 de julio de 2012 29  MMC: Reinforcements o Particulates or whiskers o Fibers ▪ Continuous ▪ Discontinuous In many MMCs, Reinforcements coating is needed: No direct fiber-fiber or fiber-matrix contact Improve bonding between fiber and matrix Relief stress concentration between fiber and matrix Protection of fiber during handling Instituto de Investigación Tecnológica Eva Paz Jiménez DIM-ICAI DIM-ICAI J.C.– del Escuela TécnicaJavier Real Munilla – Y. Ballesteros Superior de Ingeniería(2013-2014) ICAI 05 de julio de 2012 30  MMC: Reinforcements o Ceramic reinforcements Particles SiC, TiC, Al2O3 Discontinuous fibers Whiskers TiB2, SiC, Al2O3 Short Fibers Glass, SiC, Al2O3 Continuous fibers Oxide Glass, Al2O3, ZrO2 Non- oxide B, C, SiC, BN Instituto de Investigación Tecnológica Eva Paz Jiménez DIM-ICAI DIM-ICAI J.C.– del Escuela TécnicaJavier Real Munilla – Y. Ballesteros Superior de Ingeniería(2013-2014) ICAI 05 de julio de 2012 31  Ceramic Matrix Composites (CMC) o Ceramics: Inorganic, nonmetallic. Varying crystallinity Ionic and covalent bonds ▪ High electrical and thermal insulators ▪ High strength and hardness ▪ Low ductibility, low plastic deformation ▪ High to very high melting temperature ▪ High wear and chemical resistance ▪ Usually paramagnetic *Exceptions can be found to all of them!! Instituto de Investigación Tecnológica Eva Paz Jiménez DIM-ICAI DIM-ICAI J.C.– del Escuela TécnicaJavier Real Munilla – Y. Ballesteros Superior de Ingeniería(2013-2014) ICAI 05 de julio de 2012 32  Ceramic Matrix Composites o Usually CMC are Ceramics for both matrix and reinforcement… Then, why CMC? ✓ Combination of properties ✓ Fracture toughness increased ✓ Thermal shock resistance improved ✓ Possibility of anisotropy ✓ Effects at atomic level: grain boundaries, chemical resistance (oxidation!)… Same reinforcements as for MMC… Usually C, SiC, Al2O3 Particulates or Fibers (Ceramic Fiber Reinforced Ceramic CFRC) Instituto de Investigación Tecnológica Eva Paz Jiménez DIM-ICAI DIM-ICAI J.C.– del Escuela TécnicaJavier Real Munilla – Y. Ballesteros Superior de Ingeniería(2013-2014) ICAI 05 de julio de 2012 33  Ceramic Matrix Composites o Brake disks ✓ Wear improvement (up to 300.000 km) ✓ Corrosion resistance (humidity, salt water) ✓ No deformation or heat effects during braking o Ceramic bearings ✓ Wear improvement (longer service life) ✓ Less friction, less deformation ✓ Electrical insulator ✓ Less vibrations Instituto de Investigación Tecnológica Eva Paz Jiménez DIM-ICAI DIM-ICAI J.C.– del Escuela TécnicaJavier Real Munilla – Y. Ballesteros Superior de Ingeniería(2013-2014) ICAI 05 de julio de 2012 34  Ceramic Matrix Composites: CFRC ✓ FIBERS: Structural applications for ultra high temperatures Temperatures up to 2000 ºC Oxide interface coatings: oxidation protection for the carbon fibers SEM micrograph of SiNC fiber in SiC matrix Instituto de Investigación Tecnológica Eva Paz Jiménez DIM-ICAI DIM-ICAI J.C.– del Escuela TécnicaJavier Real Munilla – Y. Ballesteros Superior de Ingeniería(2013-2014) ICAI 05 de julio de 2012 35  Polymeric Matrix Composites (PMC) ▪ Polymers properties: ✓ Molecules composed of repeated monomers ✓ Organic ✓ Covalent bonds and weak bonds ✓ Semicrystalline to amorph (glasses) ✓ Broad range of properties based on composition, chains arrangement, … ✓ Interesting mechanical properties are posible: Viscoelasticity, low friction,… ✓ Chemical and radiation resistance are posible Usually low mechanical properties (strength, modulus, hardness) Low temperature resistance Instituto de Investigación Tecnológica Eva Paz Jiménez DIM-ICAI DIM-ICAI J.C.– del Escuela TécnicaJavier Real Munilla – Y. Ballesteros Superior de Ingeniería(2013-2014) ICAI 05 de julio de 2012 36  Polymeric Matrix ▪ Polymer classifications based on: ✓ “High” temperature behavior ✓ Polymerization ✓ Traction properties ✓ Fracture properties ✓ Optical properties ✓ Chemical properties ✓ Flammability ✓ … Instituto de Investigación Tecnológica Eva Paz Jiménez DIM-ICAI DIM-ICAI J.C.– del Escuela TécnicaJavier Real Munilla – Y. Ballesteros Superior de Ingeniería(2013-2014) ICAI 05 de julio de 2012 37  Polymeric Matrix: Thermosetting Resins ▪ Thermoset Resins: ▪ Cannot be remelted ▪ 3-d molecular chains – cross linking ▪ Brittle ▪ Usually Rigid ▪ Higher electrical, chemical, thermal resistance Epoxy Phenolics Polyester Vinylester Cyanate esters Polyimides Instituto de Investigación Tecnológica Eva Paz Jiménez DIM-ICAI DIM-ICAI J.C.– del Escuela TécnicaJavier Real Munilla – Y. Ballesteros Superior de Ingeniería(2013-2014) ICAI 05 de julio de 2012 38  Polymeric Matrix: Thermosetting Resins ▪ Epoxies: ▪ Very versatile. Broad range of properties and processing capabilities ▪ Epoxies are the most widely used resin materials for PMC Epoxide generic functional group ▪ They can be used standalone for: ✓ Adhesives ✓ Coatings ✓ Electrical insulator Epoxy Molecule ▪ Curing (2 components at least): ✓ Two biepoxic molecules ✓ Biepoxic molecule + hardener (+catalyst) + Specific conditions (temperature, radiation, …) Instituto de Investigación Tecnológica Eva Paz Jiménez DIM-ICAI DIM-ICAI J.C.– del Escuela TécnicaJavier Real Munilla – Y. Ballesteros Superior de Ingeniería(2013-2014) ICAI 05 de julio de 2012 39  Polymeric Matrix: Thermosetting Resins ▪ Epoxies: ▪ Choice of components, hardeners and curing environment for: ✓ Actual material properties ✓ Curing rate – working time ✓ Manufacturing method Example: Same resin, 3 different hardeners (west system epoxy resin 105) Fast H. Slow H. Extra slow H. Instituto de Investigación Tecnológica Eva Paz Jiménez DIM-ICAI DIM-ICAI J.C.– del Escuela TécnicaJavier Real Munilla – Y. Ballesteros Superior de Ingeniería(2013-2014) ICAI 05 de julio de 2012 40  Polymeric Matrix: Thermosetting Resins ▪ Epoxies: ▪ Typical service temperature: min (0 K to -20ºC), max (100 ºC to 200 ºC) ▪ Usual commercial forms: Liquid (not mixed) Semi-solid (mixed): Prepregs. Must be kept cold. Instituto de Investigación Tecnológica Eva Paz Jiménez DIM-ICAI DIM-ICAI J.C.– del Escuela TécnicaJavier Real Munilla – Y. Ballesteros Superior de Ingeniería(2013-2014) ICAI 05 de julio de 2012 41  Polymeric Matrix: Thermosetting Resins ▪ Phenolic Resins: ▪ Phenol formaldehyde – Most known example is Bakelite ▪ Low smoke and low toxicity ▪ High Temp (220 ºC), high wear resistance, hard (compared to polymers) ▪ Used stand-alone for electronic equipment ▪ As PMC matrix: ✓ Brake pads ✓ Aircrafts ✓ Construction – Interior design Instituto de Investigación Tecnológica Eva Paz Jiménez DIM-ICAI DIM-ICAI J.C.– del Escuela TécnicaJavier Real Munilla – Y. Ballesteros Superior de Ingeniería(2013-2014) ICAI 05 de julio de 2012 42  Polymeric Matrix: Thermosetting Resins ▪ Thermosetting Polyesters: ✓ Great corrosion resistance Styrene emissions during fabrication ✓ Lowest cost, good general properties ✓ Glass fibers as reinforcements ✓ Non- structural parts ▪ Vinyl ester resin: ✓ Greatest corrosion resistance and ✓ Marine, water applications least water absorption ✓ Low cost, good general properties ✓ Glass fibers as reinforcements ✓ Non- structural parts and coatings Instituto de Investigación Tecnológica Eva Paz Jiménez DIM-ICAI DIM-ICAI J.C.– del Escuela TécnicaJavier Real Munilla – Y. Ballesteros Superior de Ingeniería(2013-2014) ICAI 05 de julio de 2012 43  Polymeric Matrix: Thermosetting Resins ▪ Cyanate Esters: ✓ Best general performance Costs ✓ High Tg temperature ✓ Reinforcements: Carbon fibers/particles,… ✓ Aircrafts, military ✓ Structural parts ▪ Polyimide: ✓ Highest Tg temperature Difficult processing ✓ Flexible ✓ Military, spacecrafts ✓ Good general properties ✓ Flexible cable insulator ✓ Including chemical, flame and radiation resistance Instituto de Investigación Tecnológica Eva Paz Jiménez DIM-ICAI DIM-ICAI J.C.– del Escuela TécnicaJavier Real Munilla – Y. Ballesteros Superior de Ingeniería(2013-2014) ICAI 05 de julio de 2012 44  Polymeric Matrix: Thermoplastic Resins ▪ Thermoplastic Resins: ▪ Can be remelted and solidified ▪ No cross linking: Flexible, deformable ▪ Ductile, thougher than thermosets ▪ Lower stiffness and strength ▪ Amorphous or semi-crystalline ▪ Susceptible to solvents, corrosion ▪ Easy to repair ▪ Higher viscosity Polypropylene Nylon PEEK Polyester Teflon Instituto de Investigación Tecnológica Eva Paz Jiménez DIM-ICAI DIM-ICAI J.C.– del Escuela TécnicaJavier Real Munilla – Y. Ballesteros Superior de Ingeniería(2013-2014) ICAI 05 de julio de 2012 45  Polymeric Matrix: Thermoplastic Resins ▪ Nylon (Polyamide): ▪ Teflon (PTFE): ✓ Widely used alone or reinforced ✓ Great solvent resistance ✓ A lot of nylon formulations: ✓ Self-lubricated Nylon 66, Kevlar… ✓ High melting point (327º C) Some of them patented: Kevlar, Nomex, … Natural fibers: Wool, silk ✓ Quite special material! ✓ Fabrics or bulk material ✓ As PMC, main use is biomedical ✓ Vibration dumping ✓ FRP (nylon) has best impact properties Absorb moisture Instituto de Investigación Tecnológica Eva Paz Jiménez DIM-ICAI DIM-ICAI J.C.– del Escuela TécnicaJavier Real Munilla – Y. Ballesteros Superior de Ingeniería(2013-2014) ICAI 05 de julio de 2012 46  Polymeric Matrix: Thermoplastic Resins ▪ Polypropylene (PP): ✓ Lowest density ✓ Low cost, fatigue resistance ✓ Machine parts, fans,… ✓ GFRP (PP) is a versatile option GR polypropylene air intake manifolds of a car ▪ PEEK (Polyetheretherketone): ✓ High Tg for thermoplastic High cost ✓ Low moisture absorption ✓ High toughness ✓ CFRP for spacecrafts, structural parts Instituto de Investigación Tecnológica Eva Paz Jiménez DIM-ICAI DIM-ICAI J.C.– del Escuela TécnicaJavier Real Munilla – Y. Ballesteros Superior de Ingeniería(2013-2014) ICAI 05 de julio de 2012 47  Polymeric Matrix Composites (PMC) Reinforcements for PMC Typical materials Fibers shape Fabrics: Carbon Short Unidirectional Glass Long Woven Aramid Multiaxial Continuous Discontinuous Fabric Non-fabric Instituto de Investigación Tecnológica Eva Paz Jiménez DIM-ICAI DIM-ICAI J.C.– del Escuela TécnicaJavier Real Munilla – Y. Ballesteros Superior de Ingeniería(2013-2014) ICAI 05 de julio de 2012 48  Polymeric Matrix Comp.: Reinforcement materials ▪ Glass Fiber (GF) ▪ Carbon Fiber (CF) ▪ Aramid Fibers ✓ Cheapest fiber ✓ Highest modulus of ✓ Most popular: Kevlar ✓ Several types. elasticity ✓ Best thermal resistance Properties can vary ✓ Electrical conductor + thermal insulator based on ingredients. ✓ Best chemical ✓ Best abrasion resistance ✓ Main ingredient: Silica resistance ✓ Best fatigue resistance sand (50 – 60%) ✓ Sizing can be added to basic glass to improve resin bonding Less temperature Expensive Sensitive to UV radiation resistance and acid, bases, oxidizers It is always black Absorb water. No so good “Sensitive” to fatigue matrix bonding Instituto de Investigación Tecnológica Eva Paz Jiménez DIM-ICAI DIM-ICAI J.C.– del Escuela TécnicaJavier Real Munilla – Y. Ballesteros Superior de Ingeniería(2013-2014) ICAI 05 de julio de 2012 49  Polymeric Matrix Comp.: Reinforcement materials ▪ Glass Fiber (GF) ✓ E-Glass Electrical applications (insulator) ✓ C- Glass Improve Corrosion resistance ✓ S- Glass High temperature and Strength ✓ E-CR Glass Use at CRyogenic temperatures ✓ D- Glass Low Dielectric constant Transparent UV and higher λ (radar) SiO2 > 95%, High T Instituto de Investigación Tecnológica Eva Paz Jiménez DIM-ICAI DIM-ICAI J.C.– del Escuela TécnicaJavier Real Munilla – Y. Ballesteros Superior de Ingeniería(2013-2014) ICAI 05 de julio de 2012 50  Polymeric Matrix Comp.: Reinforcement materials ▪ Glass fibers (GF) Manufacturing (I) Raw materials Long filaments Melting through bushing mixing holes Instituto de Investigación Tecnológica Eva Paz Jiménez DIM-ICAI DIM-ICAI J.C.– del Escuela TécnicaJavier Real Munilla – Y. Ballesteros Superior de Ingeniería(2013-2014) ICAI 05 de julio de 2012 51  Polymeric Matrix Comp.: Reinforcement materials ▪ Glass fibers (GF) Manufacturing (II) Bushing Cool down Sizing/Coatings Forming strands b) Short fibers/Mat: CHOPPER a) Long fibers: WINDERS (Optional): Fabrics Instituto de Investigación Tecnológica Eva Paz Jiménez DIM-ICAI DIM-ICAI J.C.– del Escuela TécnicaJavier Real Munilla – Y. Ballesteros Superior de Ingeniería(2013-2014) ICAI 05 de julio de 2012 52  Polymeric Matrix Comp.: Reinforcement materials ▪ Glass fibers (GF) Manufacturing (IV) ✓ Fabrics Instituto de Investigación Tecnológica Eva Paz Jiménez DIM-ICAI DIM-ICAI J.C.– del Escuela TécnicaJavier Real Munilla – Y. Ballesteros Superior de Ingeniería(2013-2014) ICAI 05 de julio de 2012 53  Polymeric Matrix Comp.: Reinforcement materials ▪ Glass fibers (GF) Manufacturing (V) ✓ Chopped (Short fibers / mat) Instituto de Investigación Tecnológica Eva Paz Jiménez DIM-ICAI DIM-ICAI J.C.– del Escuela TécnicaJavier Real Munilla – Y. Ballesteros Superior de Ingeniería(2013-2014) ICAI 05 de julio de 2012 54  Polymeric Matrix Comp.: Reinforcement materials ▪ Glass fibers: Basic forms (mov) Instituto de Investigación Tecnológica Eva Paz Jiménez DIM-ICAI DIM-ICAI J.C.– del Escuela TécnicaJavier Real Munilla – Y. Ballesteros Superior de Ingeniería(2013-2014) ICAI 05 de julio de 2012 55  Polymeric Matrix Comp.: Reinforcement materials ▪ Carbon fibers (CF) ▪ Organic precursor Pyrolysis (Carbonize) Polymerization ✓ PAN (Longitudinal tension) ✓ High T ✓ Pitch (coal, petroleum) ✓ No oxygen Stabilization Coating Winding Instituto de Investigación Tecnológica Eva Paz Jiménez DIM-ICAI DIM-ICAI J.C.– del Escuela TécnicaJavier Real Munilla – Y. Ballesteros Superior de Ingeniería(2013-2014) ICAI 05 de julio de 2012 56  Polymeric Matrix Comp.: Reinforcement materials ▪ Carbon fibers (CF) Designation (Common) T700 C – 1200 M550 - 1000 Number of filaments Twist Blank: Twisted yarn B: Untwisted yarn C: Never twisted Properties (Number) S: Tensile Strength M: Modulus Instituto de Investigación Tecnológica Eva Paz Jiménez DIM-ICAI DIM-ICAI J.C.– del Escuela TécnicaJavier Real Munilla – Y. Ballesteros Superior de Ingeniería(2013-2014) ICAI 05 de julio de 2012 57  Polymeric Matrix Comp.: Reinforcement shapes Woven Fabrics Harness number (vert) Flat components Shaft number (horiz) Residual stresses (curvature) Contours adaptability Asimmetry between faces Plain Satin Less stresses Smoother surface Low density of fibers Twill (2/2) Leno Instituto de Investigación Tecnológica Eva Paz Jiménez DIM-ICAI DIM-ICAI J.C.– del Escuela TécnicaJavier Real Munilla – Y. Ballesteros Superior de Ingeniería(2013-2014) ICAI 05 de julio de 2012 58  Polymeric Matrix Comp.: Reinforcement shapes ▪ Laminates Remember! Plies properties depend on orientation Lamina can be made by plies with different orientations: Custom anisotropic properties Instituto de Investigación Tecnológica Eva Paz Jiménez DIM-ICAI DIM-ICAI J.C.– del Escuela TécnicaJavier Real Munilla – Y. Ballesteros Superior de Ingeniería(2013-2014) ICAI 05 de julio de 2012 59  Polymeric Matrix Comp.: Prepegs Prepegs ✓ Typical commercial form Need for cooling storage ✓ Designation: Fiber, fabric, resin (or resin will cure) ✓ Reinforcement and matrix mixed in Higher material cost advanced: (Additional step and raw Resin impregnated reinforcement material on manufacturing process) (not cured) ✓ Usually fiber, fabric or mat in flat form ✓ Ready for part manufacturing ✓ Easier part manufacturing Instituto de Investigación Tecnológica Eva Paz Jiménez DIM-ICAI DIM-ICAI J.C.– del Escuela TécnicaJavier Real Munilla – Y. Ballesteros Superior de Ingeniería(2013-2014) ICAI 05 de julio de 2012 60  Polymeric Matrix Comp.: Prepegs Prepegs Instituto de Investigación Tecnológica Eva Paz Jiménez DIM-ICAI DIM-ICAI J.C.– del Escuela TécnicaJavier Real Munilla – Y. Ballesteros Superior de Ingeniería(2013-2014) ICAI 05 de julio de 2012 61  Quantitative Comparation (Mechanical) Instituto de Investigación Tecnológica Eva Paz Jiménez DIM-ICAI DIM-ICAI J.C.– del Escuela TécnicaJavier Real Munilla – Y. Ballesteros Superior de Ingeniería(2013-2014) ICAI 05 de julio de 2012 62  Composite structures: Sandwich Sandwich structure Optimized structure FACES (Skin): 2D structural parts: FRP, metals Instituto de Investigación Tecnológica Eva Paz Jiménez DIM-ICAI DIM-ICAI J.C.– del Escuela TécnicaJavier Real Munilla – Y. Ballesteros Superior de Ingeniería(2013-2014) ICAI 05 de julio de 2012 63  Composite structures: Sandwich Sandwich structure HONEYCOMBS: CORE: Light weight FOAMS: Polymers: Foams Aluminum PVC ABS PS Metals, Polymers: PU PC Honeycomb PP … Additional benefits: Posible insulator core Open / Closed Core Faces & Core interface: Adhesive bonding Brazing Instituto de Investigación Tecnológica Eva Paz Jiménez DIM-ICAI DIM-ICAI J.C.– del Escuela TécnicaJavier Real Munilla – Y. Ballesteros Superior de Ingeniería(2013-2014) ICAI 05 de julio de 2012 64  Composite structures: Sandwich Cores Aluminum Honeycomb Thermoplastics Foams (Polymers) Cheap Cheapest Low weight Great ratio Non-structural parts Non-structural parts strength/weight Difficult bonding to PU: Acoustic Insul. Galvanic corrosion skin PS: Easy Manufact. when used with ABS for mechanical carbon skins! PVC: Low temp. PC: for heat, radiation PP: Chemical Resis. Instituto de Investigación Tecnológica Eva Paz Jiménez DIM-ICAI DIM-ICAI J.C.– del Escuela TécnicaJavier Real Munilla – Y. Ballesteros Superior de Ingeniería(2013-2014) ICAI 05 de julio de 2012 65 Materiales avanzados y técnicas de unión Advanced Materials and Joining Manufacturing Parts  Composite Materials: Manufacturing techniques ▪ A lot of CM manufacturing methods available ▪ The best manufacturing method for each part will depend on: ✓ Material properties (Matrix, Reinforcements) ✓ Shape (constituents, parts) ✓ Composite properties ✓ Tolerances & Quality needs ✓ Experience & Availability ✓ Costs Instituto de Investigación Tecnológica Eva Paz Jiménez DIM-ICAI Javier Munilla Escuela Técnica Superior de Ingeniería ICAI 05 de julio de 2012 2 2  Product fabrication (PMCs) ▪ POLYMERIC MATRIX COMPOSITES: MANUFACTURING At this stage, “raw” composite material is manufactured Simple geometries can be made as rods, sheets,… But also complex geometries (near to final part shape) can be manufactured using specific techniques Material properties will depend on (but not only): Constituents Volume fractions Shape, geometry, orientation Processing quality Additives Processing parameters: (Temperature, pressure, radiation,…) Instituto de Investigación Tecnológica Eva Paz Jiménez DIM-ICAI Javier Munilla Escuela Técnica Superior de Ingeniería ICAI 05 de julio de 2012 3 3  PMC Processing IMPREGNATION CONSOLIDATION Fibers and resin are mixed Intimate contact between matrix and Resin should flow around fiber the fibers Remove air, improve wettability Viscosity & capillarity Resin flow + elastic fiber deformation Pressure LAY-UP SOLIDIFICATION Distribution and arrangement Matrix polymerization (curing, if needed) of the fibers and/or the Temperature, time compound Amount of material: Thickness, number of turns, layers… Instituto de Investigación Tecnológica Eva Paz Jiménez DIM-ICAI Javier Munilla Escuela Técnica Superior de Ingeniería ICAI 05 de julio de 2012 4 4  PMC Processing Thermosetting Polymers: Thermoplastic Polymers: ✓ Liquid state at ambient T (Usually) Solid state at ambient T (Usually) Low viscosity (10 – 104 cp) Melting required ✓ Easier processing High viscosity (104 – 108 cp) ✓ Less heat and pressure needed More heat and pressure needed ✓ Lower cost tooling ✓ Short cycle time (no chemical Longer curing time reactions involved) Once cured, cannot be reformed ✓ They can be reshaped Difficult recycling ✓ They are easy to recycle Instituto de Investigación Tecnológica Eva Paz Jiménez DIM-ICAI Javier Munilla Escuela Técnica Superior de Ingeniería ICAI 05 de julio de 2012 5 5  PMC Processing Instituto de Investigación Tecnológica Eva Paz Jiménez DIM-ICAI Javier Munilla Escuela Técnica Superior de Ingeniería ICAI 05 de julio de 2012 6 6  PMC Processing Hand Lay-up ▪ Fabrics (dry), prepegs (wet) ▪ Manual manufacturing: ▪ Quality highly dependent on operator skill ▪ Open mold, release agent to facilitate demolding ▪ Simple and little capital investment ▪ Used for medium/large size parts, low volume production, prototyping ▪ Curing can be as simple as ambient T, no covers. (Multiple options) Gel Coat Improve surface roughness Protection Coloured (optional) Epoxy / polyester resin (mov) Instituto de Investigación Tecnológica Eva Paz Jiménez DIM-ICAI Javier Munilla Escuela Técnica Superior de Ingeniería ICAI 05 de julio de 2012 7 7  PMC Processing Infusion Processes Peel Ply Surface finishing Fabric ▪ The stacks are covered by a vacuum bag Polyester ▪ Very large parts can be manufactured, no need of closed molds Release film ▪ Fibers, fabrics and massive cores can be used Surface finishing Fabric ▪ Different layers applied for release and breathe PVF, ETFE ▪ Difficult automation, manual operation needed, quite slow Breather/Bleeder Fabric ▪ Usually for small series production Polyester/PA Porous (mov) Instituto de Investigación Tecnológica Eva Paz Jiménez DIM-ICAI Javier Munilla Escuela Técnica Superior de Ingeniería ICAI 05 de julio de 2012 8 8  PMC Processing Spray-up ▪ Easy and cheap, Short fibers and (usually) thermoset resin ▪ Open mold, Medium to large parts ▪ Fabrics and prepegs can be embedded manually as required ▪ Can be automatized for better quality ▪ Overall thickness and homogeneity depend on operator skill (mov) Instituto de Investigación Tecnológica Eva Paz Jiménez DIM-ICAI Javier Munilla Escuela Técnica Superior de Ingeniería ICAI 05 de julio de 2012 9 9  PMC Processing Circular processes Filament winding ▪ Hollow, circular parts ▪ Good structural properties ▪ Fiber costs minimized, Mandrel can be expensive ▪ Bad surface quality ▪ Limited to convex shapes ▪ Winding tension (N) ▪ Improving surface: ▪ Curing: ▪ Machining ▪ Ambient T, p allowed ▪ Shrink taped before curing ▪ Faster: UV, e-beam, X-rays curing, heat ▪ Teflon-coated air breather cover chamber… ▪ Not all fiber angles are easily produced (mov) Roll wrapping: Fabrics or prepegs are used instead of fibers Instituto de Investigación Tecnológica Eva Paz Jiménez DIM-ICAI Javier Munilla Escuela Técnica Superior de Ingeniería ICAI 05 de julio de 2012 10 10  PMC Processing: Autoclave-based Processes Autoclave ▪ Pressure control (isostatic pressing) ▪ Atmospheric composition controlled ▪ Temperature controlled for heating and cooling rates ▪ The autoclave is expensive and difficult to operate ▪ Dimensions limited to the chamber ▪ Great control of curing can be achieved ▪ Vacuum bag + external pressure ✓ High volume fractions are possible ✓ Structural parts, high quality ▪ Complex parts should be spot-welded to keep positions Instituto de Investigación Tecnológica Eva Paz Jiménez DIM-ICAI Javier Munilla Escuela Técnica Superior de Ingeniería ICAI 05 de julio de 2012 11 11  PMC Processing: SMC SMC - Sheet Molding Compound ✓ Sheet of uncured thermoset resin and uniformly distributed short fibers + Maduration period (few days) Instituto de Investigación Tecnológica Eva Paz Jiménez DIM-ICAI Javier Munilla Escuela Técnica Superior de Ingeniería ICAI 05 de julio de 2012 12 12  PMC Processing: SMC SMC - Sheet Molding Compound ✓ Sheet of uncured thermoset resin and uniformly distributed short fibers ✓ Up to few mm thickness ✓ Low-cost ✓ High volume production ✓ Similar: TMC, BMC,… (Thick, Bulk…) ✓ Raw material for compression and injection processes Instituto de Investigación Tecnológica Eva Paz Jiménez DIM-ICAI Javier Munilla Escuela Técnica Superior de Ingeniería ICAI 05 de julio de 2012 13 13  PMC Processing: Molding-based Processes SMC: Molding ▪ Uses SMC as raw material (uncured thermoset & short fibers) ▪ Part quality: ✓ Press paralelism ✓ Mold quality ▪ High- volume production and low cost ▪ Automotive industry ▪ Non- structural parts, high initial investment (mov) (mov) Instituto de Investigación Tecnológica Eva Paz Jiménez DIM-ICAI Javier Munilla Escuela Técnica Superior de Ingeniería ICAI 05 de julio de 2012 14 14  PMC Processing: Molding-based Processes Mold Design (Important parameters) ✓ Shrinkage: Mold dimensions vs final part dimensions ✓ CTE compatibility between composite and mold ✓ Stiffness ✓ Surface finish ✓ Draft and corner radii Instituto de Investigación Tecnológica Eva Paz Jiménez DIM-ICAI Javier Munilla Escuela Técnica Superior de Ingeniería ICAI 05 de julio de 2012 15 15  PMC Processing: Molding-based Processes Injection molding (IM) ▪ Thermoplastic resins ✓ SRIM (Structural Reaction IM) ▪ Usually short fibers Instead of thermoplastics, liquid thermosets are used, so polymerization ▪ High- volume production and low cost occur inside the mold ✓ Blow molding Air pressure is applied before solidification to produce hollow parts Instituto de Investigación Tecnológica Eva Paz Jiménez DIM-ICAI Javier Munilla Escuela Técnica Superior de Ingeniería ICAI 05 de julio de 2012 16 16  PMC Processing: Molding-based Processes Resin Transfer Molding (RTM) ▪ First: Preform of fibers (long fibers, fabrics or even prepegs can be used) ▪ Second step: Resin is injected ▪ Low viscosity of resin is needed, so usually thermosets ▪ High level of automation ▪ Can be used for structural complex parts, up to medium volume production and large parts (mov) VARTM (Vacuum Assisted RTM) Vacuum is applied to the mold for resin flow improvement CRTM (Compression RTM) Compression is applied to the mold during curing SQRTM (Same Quality RTM). Preform is a prepeg with the same matrix resin to be injected Instituto de Investigación Tecnológica Eva Paz Jiménez DIM-ICAI Javier Munilla Escuela Técnica Superior de Ingeniería ICAI 05 de julio de 2012 17 17  PMC Processing: Molding-based Processes Pultrusion ▪ Continuous production, solid or hollow structures ▪ Constant cross-section, lineal shape ▪ Mainly of axially oriented reinforcements, but other orientations are possible using fabrics ▪ High volume production (cm/min) ▪ Impregnation: Open bath or injected by pressure ▪ Thin walls and high-tolerance parts cannot be produced (mov) (mov) Instituto de Investigación Tecnológica Eva Paz Jiménez DIM-ICAI Javier Munilla Escuela Técnica Superior de Ingeniería ICAI 05 de julio de 2012 18 18  CM Design MANUFACTURING Prod. Rate Cost Strength Size Shape Raw Material Hand lay-up Slow High Med. To High Small to large Open F+R, Prepeg Spray lay-up Medium Low Low Small to Med. Open SF RTM Medium Low to Med. Medium Small to Med. Any* Preform Compression Fast Low Med. Small to Med. Open SMC, BMC,… Injection M. Fast Low Low to Med. Small Open SF Filament W. Slow to Fast Low to High High Small to large Axisym. LF Roll W. Med. to Low to Med. High Small to Med. Axisym. Prepeg Fast Pultrusion Fast Low to Med. High** (1D) Small to Med** Tubular LF Instituto de Investigación Tecnológica